Irritable Bowel Syndrome (IBS) is a chronic condition which affects 15% to 20% of North Americans. IBS is defined as abdominal pain/discomfort in the mid or lower gastrointestinal (GI) tract, associated with defecation or a change in bowel patterns with features of disordered defecation. The chronic symptoms of IBS have been linked with decreased quality of life, decreased work productivity and increased healthcare utilization. Current therapies include dietary modification, psychotherapy, probiotics, and pharmaceutical agents. None of these therapies are curative, some have life threatening side effects and results from research have been equivocal. Acupuncture/Moxibustion (Acu/Moxa), used in traditional Chinese medicine (TCM), is used to manage various GI disorders. However, few acupuncture studies have had the necessary rigor to evaluate this therapy. This application follows accepted standards of rigorous clinical trials with the primary aim to investigate the efficacy of Acu/Moxa in a randomized, blinded, sham/placebo controlled study to reduce abdominal pain/discomfort and IBS secondary supporting symptoms (IBS-SecS) (intestinal gas, bloating, stool consistency). 183 adults, diagnosed with IBS-Constipation (IBS-C) based on the ROME III criteria, will be randomized to one of three conditions: 1) Protocol-oriented Acu/Moxa (Standard); 2) Patient-oriented Acu/Moxa (Individualized TCM diagnosis and point prescription), or 3) Sham Acu/Placebo Moxa (Control). All subjects will attend a screening/intake session, twice weekly treatment sessions for 4 weeks, one weekly treatment sessions for 4 weeks, and 2 long-term non-treatment follow-up sessions at weeks 12 and 24. A Diagnostic Acupuncturist (blinded to treatment assignment) assesses each subject and prescribes Acu-points; a licensed Treating Acupuncturist trained in TCM delivers the intervention according to the randomization assignment; and all subjects complete the same instruments and daily symptom diaries for the duration of the study. Secondary aims assess treatment group differences in patient-rated global improvement, quality of life and psychological distress (SA#2); healthcare resource utilization and work productivity loss (SA#3); and explore the relationship between TCM diagnoses and response to treatment (SA#4). Power analysis to detect clinically meaningful differences in group-by-time interactions with 80% power, 5% alpha, a linear mixed model for repeated measures (baseline, 4, 8, 12 & 24 wks) calls for 55 S/group: total=183 when 18 additional subjects are included for attrition. Intent-to-treat analysis of group differences in primary and secondary outcomes will also use mixed models with fixed effects for group, time and their interaction, and empirically determined covariance structure and baseline level of the outcome as a continuous covariate. Secondary analyses will estimate the influence of baseline confounders and time-dependent variables to the estimate of the treatment effect.